Early Vigor of a Pyramiding Line Containing Two Quantitative Trait Loci, Phosphorus Uptake 1 (Pup1) and Anaerobic Germination 1 (AG1) in Rice (O. Sativa L.)

Na-Hyun Shin,Soocheul Yoo,Joong Hyoun Chin,Jong-Hee Lee,Jae-Hyuk Han,Kihwan Song,Su Jang,Hee-Jong Koh

doi:10.3390/agriculture10100453

Abstract

Direct-seeded rice is one of the solutions against the issues of limited labor and time in the rice cropping system. Improved useful traits, such as fertilizer uptake and anaerobic germination, are needed to increase yield and efficiency in the direct seeding system in rice. Pup1 (Phosphorous uptake1) containing PSTOL1 is useful in improving the phosphate uptake under rainfed/upland conditions. OsTPP7 is the major gene of AG1 (Anaerobic Germination), which shows anaerobic germination. IR64-Pup1-AG1 (I-PA) was developed by pyramiding Pup1 and AG1. Around 20% of the chromosomal segments from the donor remained in I-PA. Phenotypic analysis revealed that I-PA showed better phenotypic performance under low and normal P conditions by enhancing the root system and tiller numbers during the early stage. Significantly better P uptake capacity of I-PA was observed upon a P-supplied soil condition. The coleoptile length and germination rate of I-PA showed tolerance under anaerobic-germinated conditions. PSTOL1 and OsTPP7 were independently expressed under different P conditions of soils, as well as anaerobic conditions. The newly developed breeding lines, I-PA, showed early vigor capacity through a high number of tillers, better P uptake, and germination in low-oxygen conditions. It will be a useful and improved breeding line for direct seeding rice breeding programs.

Highlights

Rice is a staple food for more than half of the human population
The plant that lost the Sub1 quantitative trait locus (QTL) was found in the process of crossing I-Pup1 and I-SA, and was developed to I-PA in this study
Chromosome segments originating from I-Pup1 and I-AG1 were detected in

Summary

Introduction

Rice is a staple food for more than half of the human population. Increasing water scarcity in paddy fields and increasing labor costs in rice cropping systems are challenging the food security systems of Asian countries dependent on rice. Pre-germinated rice seeds or seedlings are broadcasted in the field in the case of direct-seeded rice (DSR) [1]. In the DSR system, abiotic stresses in the early. The development of rice for the wet direct seeding system needs those traits, because the manpower to take care of fields is lacking, and the uneven surface of soils is common, especially at the seedling period. Rice is one of the unique crops that is cultivated in submerged soils, due to its developed aerenchyma that can mitigate the stresses from anoxia [2]. Rice is one of the unique crops that is cultivated in submerged soils, due to its developed aerenchyma that can mitigate the stresses from anoxia [2]. qAG-9-2, or AG1, derived from Khao Hlan

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